I didn't expect to live long enough to write this when, 20 years ago today, my doctor called to tell me that my HIV test had come back positive. The news hit me like a bomb; hyperbole or not, back then it was still pretty much considered a death sentence.

Can we help T cells, or hinder pathogens or cancer cells, by fiddling with their random walk statistics? With so much that remains to be understood, one thing is clear -- it will take the combined efforts of scientists to answer these questions.